SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '775bdaae7823c7850c4d9b2b9652136421a52540785f6920699f76b6e4b41d91' 
  AND token = 'hyswde0uxmeObv80H2/+suJloTrlpeeS0QnWY9DU57o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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