SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73fb698e42ced56a00cac65eec9b7735b1731cd2efc9579b044a50e7b210a07a' 
  AND token = 'LmCS4u8x1sHytWcGB5JWkwRSfUJu4cIdamdzHmzaaLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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