SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84f4995f66142a5824502d5ca3513f4150ef54ab4a5f7bbdb31e2d70440de94b' 
  AND token = 'U+ep+fGnDT2CAWU9TO+lBNsSFJ2GyVVqc0vBVDXGL7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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