SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c5d0b9d7585136feef71807fcb827911002a0ca0c20651f4957563538fc5b8' 
  AND token = 'h5s3NewqncmVkHJJ8s1+uj7qTc/SGVcg9QPiVAOPalk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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