SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f849644b2cd587fab631d95ab5545cf9efc4b1d4aafbff136398ff1271a84887' 
  AND token = 'L43yJp1/kDDzi489c1CTnK2wAViSJBgMVYqb9Ud49Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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