SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18f6d236791cabb49eccf155846643a4a8c27367a3e7a04295a8466c7ec15a69' 
  AND token = 'dYI8HiJxCRET9DNEm0z6NHe8aQEK3QjBWI8QWS8tiUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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