SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ee54fb1427dbf9415a4b701097cc34d9fb7e6061f1838291dcc10bc6cb75bc0' 
  AND token = 'zrXtsdCzsVjyBWwGsHuiHek/83s6yCqXRM6Myh6i7mo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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