SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d94b119b32ffa45824e5a3e9f7b5b4e1da0ef59c67d051900a942d078d31d0d' 
  AND token = 'NIdHbt2m1CZnKdTYbAo9jsY4voW86Sf7NGBv+Mwu2ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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