SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '279da1a1bb6df2deb15f48c6e2e803947ffe84390f721af0eec024addbcaa9f3' 
  AND token = 'Slrit/2roc5h+aaeuepyVmobj0qKz50W/QU1gHuAckk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

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