SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54d2ea738125271f3f939fda4895d535f4d077bdd4d1051e1122ade08a05389d' 
  AND token = '/Of91OBBC1ZOWuvU20TM0Z2xA/UIteHeevjlk/dZldw=' 
  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