SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a48126a1249ba6d9d00d6d2531a84626dd5fbaaf224bece01836fb4699e989d6' 
  AND token = 'QBlcTJGLprfW+jOfVLIxB7iIUYflDP1rpmHcE9lFEXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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