SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b7d3b94a20c371e2b1cef70091a13b943dfa3af5e235cffbc6004f9c9c36727' 
  AND token = 'CJrNVmw4DmkBqcdbwet7VKVzGiEGuM1Y+A7CKPzOdH8=' 
  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"
    }
  }
}