SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a53a24f0bc2a083a09aba0b5fbdc75147ad57922564a48257204f26a1f5f6812' 
  AND token = 'dy1VR0+YlqKpJ/jdsdHndXu/7Ldb5zyw5CGOIZr1CLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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