SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc197c7b8937b5e56c83d2a4f1223f0d092dd129b6cd4b60bf649bb2583e3769' 
  AND token = 'SQHvSkkYs+H4o/FHl6Uv4W+bBlQwE48I+gP9GPtnjtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}