SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e6c136a14eacc5e8f076d50f8a97c630a2bf34ed30ab8e030eb6d0bf75d4e69' 
  AND token = '7Ksucvz6uZSLYA1+iGXT/xYVyOyRxfrPGP7JpvJQDow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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