SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ca8d5e4b7bbd48ccb36301ca045a775ada5fee703daa367337e07d22877126c' 
  AND token = 'BzpLVeqK59+wCTFFQziG7uSmji8rflDomH+5MlJZTwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables