SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec4a434755860cb2bd5eb97fadce3cec68fc3b7c80d042185b065322633a2d0b' 
  AND token = 'SfZXRfjY0ymvUtcX0KHHJzjbYoZekU3vIXSfe3P64+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

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