SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e7fab8a2240b2707e6ad438a554a0d1fd15e6edff42acfff521ccebd0dd0051' 
  AND token = 'QRAoc03YEoZijTj7vDR40ty+0hiE0Bt7jgSd4NS+420=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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