SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b06c29f00997b81f5335e79b703e7340a7e7e1bcf4f77701b0fe7dff5f2018' 
  AND token = 'XcWG2GkhlnqCGiE2RVgRN34o6ZaObKAwY7CNXV5aztY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

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