SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef952a75b3bafe02242ae89a5c68a71b5370d8f3b22460ae543e70cf1538d4f9' 
  AND token = '3jkftK8usasWpQoitEBeVrBwDrxx3xpo1dqaefn9n40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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