SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b364e15842b846943410015d88c0942ea74138125575c430718d7e17f1b7b3f7' 
  AND token = 'b8b5uaRIR4HWcQxqZ+BQl1KNZasZ/iVo0aCPYQTNe5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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