SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '37755d150690236697f62f9ccc2f60d8b500448bb763199dbfb5eb2533dd7403' 
  AND token = '5hTzHllhqQLf6ulauSgsEv4ii714LNU3BtGFG6jr9lY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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