SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328a09446cf500edd7c80373489c9f5d0b90191a704e7fb1db6ad8df71c28d85' 
  AND token = 'jF0hb9MRBW9DJvPKwFVp8UAs9NE9Wn08XOL0OQmi2O8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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