SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8a49b37e1ddba8815053ec2ce57e2ecdad1bed8ea56ef98e21c2efd46c83088' 
  AND token = 'f22o0tIMuJvliflLWTsVQul5LRmPkGlZXFnvTA0+FM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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