SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a80c03154ae9e4b829b3968aa4306f78981a06e8b736c0280f5d1256c652e21' 
  AND token = '+K/OPw/SlQxPLMZE3rTmIDYnBTsAdgk5yymvWn9xfVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}