SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90714b5dc72ccbf18e595a6c0e33b357fe525ee5d9f7dfe375d05faf14313490' 
  AND token = '2K9mb2zI7l65hlddqmdcxKQxKl3awOke3Qm/Z4ySbWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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