SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '78941c64cdfe126f6feea00c396fd0ae83c5efb969a204b2f84ffd478ee8d586' 
  AND token = 'kyl7VzWW+9daXHkWsiU48v249elvvvUIvmCeC1txZlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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