SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57a8894e5a6ae55e528e12c2218f84385149d29259a7f1d7f88cc90b6aad5b8a' 
  AND token = '+x6gt9iu+Tzv2N3RdZejpF8+mptZsnIbJVQRGgllAoQ=' 
  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