SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8309280b7d654f9d59887387ba05c0220de1c66979af0451f603f21b454b67b6' 
  AND token = '7Nv+SW4Jmu4yShz2lwgFfPBU1wIVJN1T4pf4U6DImNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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