SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33d38ad41be22366840bea4564f706b0f6d74383dc3ff3609f6187eced999826' 
  AND token = 'qTvSm4tHmKPis5VoayMqQn8v8XkCRa9xO5xfwr4N3kE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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