SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4145cb09094d7ca308b30f4a19b4076c1df3806a45947e590fbe78f0eeaef6e' 
  AND token = 'qDYMlbkOH2/6ndSsSe4NsNhrD5KiAsjs9AEayBBbYQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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