SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af751abd0a5e83e95483feeb6c0cdebaa0019eaf10c517b20b5798a5a1728e9c' 
  AND token = 'CXhhzmocWPyeVkFBWiUfKNW9Zi+T3wvWv/lrKO31o4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}