SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '210decbcec134c23bec35c20298ad5e38c07f44fb858d7f7267745d5d68f6aac' 
  AND token = 't4558D+CbFxC8OZ8Bik0Oh4RhpDONGFNjJksyQL538U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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