SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c87d74e3e6a0f023e668954688c15353c8109ea935c181fed90c670099102a06' 
  AND token = '/ZoEaJj6eYzQQgBO3PD2sHqBn1vM0v95qfZ8PkA5i8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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