SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c55d5df114d8a8c05d607cf6b4acd85053a6f9fe8004241cdf5cbba7b39bef6' 
  AND token = 'HBd445JJ+5kD/G6QRdmZd4Xe4rFNgN0Vn0uBbiIr8zo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

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