SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27dade42de23c61c92d65836d09910b16bed055870de2ef3a8f1fee817b3c2c5' 
  AND token = 'wDvOvu9kh/SZAMfyzZ5ZNH12vh/tdnJU9WKGm8Ls+VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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