SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af42923471fdd77458260959c6a4c3213b8e1db3159d211eedd50c81dfbad5f0' 
  AND token = '3CyowjSUEAGLdtRnw5312e+bU+f2hrt0J/jS9Z3LFhE=' 
  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