SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d7c7436ed561c4a400ed0ad3537b34b2bb89f126d5fa31c49b1d744838c134f' 
  AND token = '5gWHG9OW6j7yXqw+GUDgJ/aW7cBlHvuFYAb3kwxLY8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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