SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f7ea3b912501319adc2a13be56cd1103928cd140b273c4856714f3481ab1f227' 
  AND token = '/9sDIdkYMbjW7TzRGJBFlt2X3cuZZPRpLFHh5J0a/uA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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