SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55035b849291fb8e9e16013a2e9a99ba0ea7bb0e32d25df3ad07b98e3fe5ea2c' 
  AND token = 'khEcirXTPPlaMzlhnxJ47blTJVqK/rBv3P+5w3YgZP4=' 
  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