SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b938e4f481c24a4b0476a73bd01cdace4754009ae70e58d6c82e58b628ea4f8c' 
  AND token = 'D6kYpm7gUkW50vfqvaMvVJsvziQkfKAsdFG0CAWwamE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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