SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27af7c3cd3d1f830f02affa1029a08455134f458debfbedc9ce9bfd0665431b3' 
  AND token = 'atJIHiu7DbvNHYkTKfOy2+hqHFj691xuUeY68A8a+iY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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