SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef19596be010aafba248f8566e5556a0c9e37cb2bc21f86d675d7c0130d2e46' 
  AND token = '4MNSulKieOLBezTwUDoQqpW1LIep058zw2OjwbwDWmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}