SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '055211c6fecc1414bce3a2df8a955cdeeb2dfc339becc9a135fd6fac542bd939' 
  AND token = 'sA3MuP0Xu+kf5AVeZA1AWD5gIq0i56F+AI17h0IzZkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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