SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44736e0dd124e868ebb4666f15c907b52408ae45172d7cce5efdad45abd76ad0' 
  AND token = 't98ZQLItQKShInscStB7I0WyxENrg9mzq6tc71rjjuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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