SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e491c4ea52083ebb4f0f8913f37c8b17f680fd591bab239e4531fb0f88dee306' 
  AND token = 'lni/V59ypomGUW0NRMyVdvjJ8jkkTCOrpYYTfJYQP2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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