SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff7bbf74ced74648482bf34a30d7e5097f1a2673667e8b69135475082d5bd298' 
  AND token = 'APD/1MSSFmn5rNBTUS2GawqORDAUzdT5BRAFKUFOP+Y=' 
  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"
    }
  }
}