SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f490bbc5c935531db845f092cba491461134a8ed269151b9ae3fcb5d8e37755' 
  AND token = '6oN5a2tttbViB5eMdTTusnQY5/VdvA7M+cKjjecBnko=' 
  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"
    }
  }
}