SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7b8e0de4a21fd654bcb8e50b269377745ebdbfcd0e99642f462603f424cb808' 
  AND token = 'cftUvjPyejTuC/N9ywh+96wD7FFeew/6Lmr1VuA8NqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

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