SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350762a46bbf754d08f6a51cd0d3bd56860cf3b098799bb1aa127848a7346ce0' 
  AND token = 'I1cjEMZ0jr1iKJjG6M1C1sIHgDx+pYKVBPiZfFvc2QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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