SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '520fc4e3077ce9edaeeeff71605e6e3f5d807ff4c50bd90ba5dfcfaccdede7ec' 
  AND token = 'cTe1d+FRmfkEz101LPV9iMV644e1Hb/wDQ2aswNT67A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

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