SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '284f1950667230a73132c2451e97f3b95148ca10debe5b83aeaf223d2237f7da' 
  AND token = 'Lr4x4/sTiUjMIafqxLeT0WRFqjxdyzqvYnr12DLPJ3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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