SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a48398cd65a8dbf242ad2c2090cbfaa11d0af687665d0b7dd657ea1f0002663c' 
  AND token = 'q1u1erVkR31UxXzmvYmv6rClPTdB1CPyqqoR3yMFVDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

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