SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ef4fc474ffd9220050ab911528f9be0037a994bacd17e38ea02939a90312622c' 
  AND token = 'h5gtZcOutwvJojSN/TxW1mZVeej4K6TTPbTAYWr0FP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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