SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a65bfe78719210e751009b5f03cd39cd16a9ec13ff6926ee34337d83498cab1' 
  AND token = 'rb5/U+74v6gtvBySVOqnwmJiO1ElLq7pI8zoGxY40xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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