SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b47d05a66c6b5e645f5abde52dd257ed0fc683d13f9b2f994a06e8f748016b15' 
  AND token = '9W/cJ9BYSGsM7EnbZRAgZ6ZrwVHV9Lr47/KL1r13znM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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