SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6a89f2c6c04a557179fb3c82d280db6248f6877a0e6d54841cffe2849fb9dbb' 
  AND token = 'WVo+VkrzeFV3SobjdjBmtyhXbcCrrrH6U36seeHw/pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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