SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b62529175473be3e13f81b0e8e0a69292bb57affb63a0cd3248bbd34a9807a09' 
  AND token = 'sc8jhOOlQKw7ogxDFRbuXzJqnD03+yYIYfSzk1QnmPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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