SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6db442736fdbc97e74d29e192ac341df5d2d946fd6c59b448edc467e4eac8b63' 
  AND token = 'vHhbkXpqufgxbJKkPasnTEteCWyfHBshNYx6TduRXpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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