SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '923789098eabb515f158f34753a87af396de8622140876198dca0be895290992' 
  AND token = 'A584wpcSVl+blDxk7PHx0TROMKYp1xvBPsaYVrONf7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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